Projection Lenses

A projection lens comprises a first lens group and a second lens group, arranged sequentially along an optical axis from the projection side to the image source side.

The first lens group possesses positive refractive power. The second lens group also possesses positive refractive power and consists of a first lens, a second lens, a third lens, and a fourth lens. The first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, and the fourth lens has positive refractive power.

The first lens and the second lens are bonded together to create a cemented lens, which possesses negative refractive power. The first lens meets the condition: −0.579 ≤ f1/f ≤ −0.4, where f1 is the effective focal length of the first lens, and f is the effective focal length of the projection lens.